Electrical system for a ship

ABSTRACT

The invention relates to an electrical system for a ship, comprising generators, electrical consumers, such as electric motors, and an on-board power supply system with switchgears etc. as the components of the system. The electrical system is further characterized in that supplies sufficient electrical energy in all operating states of the ship and that the system components are automatically controlled by digitized standard modules.

This application is the national phase under 35 U.S.C. § 371 of PCTInternational Application No. PCT/DE02/00151 which has an Internationalfiling date of Jan. 18, 2002, which designated the United States ofAmerica and which claims priority on German Patent Application number DE101 04 892.0 filed Feb. 1, 2001, the entire contents of which are herebyincorporated herein by reference.

FIELD OF THE INVENTION

The invention generally relates to a marine electrical system.Preferably, it relates to a system having generators, electrical loads,such as electric motors and an on-board power supply system withswitchgear assemblies etc. as system components, with the electricalsystem ensuring that adequate electrical power is provided in alloperating states of the ship.

BACKGROUND OF THE INVENTION

Until now, measurement, control and regulation devices which operate onan analog basis have normally been used in maritime vessels, ifappropriate with an associated digital control and observation level. Amixed system such as this has admittedly been proven, but has designdisadvantages. Surprisingly, it has been found that a completelydigitized version can be more advantageous and, in particular, morecost-effective. This is particularly true when it is intended to carryout continual optimization, by reconfiguration, that is to say byexternal actions, or by way of an automatic system.

SUMMARY OF THE INVENTION

According to an embodiment of the invention, the known hybrid system isproduced by digital control and regulation based on standard modules.

BRIEF DESCRIPTION OF THE DRAWINGS

The design of the system will become evident from all of the detail ofthe attached system description, with the figures contained in thisdescription.

FIG. 1 illustrates the system configuration;

FIG. 2 illustrates a bar graph;

FIG. 3 illustrates a profile of the power supply system frequency inresponse to load changes in the power supply system (frequencyregulation with droop);

FIG. 4 illustrates the GENOP 71 connections;

FIG. 5 illustrates the Genop 71 integrated in the PMA 71 system;

FIG. 6 illustrates the Genop 71 used as an individual device;

FIG. 7 illustrates the functional relationship for generator protection;

FIG. 8 illustrates the functional relationship for disturbanceevaluation;

FIG. 9 illustrates the functional procedures for synchronization;

FIG. 10 illustrates the principle of synchronization; and

FIG. 11 illustrates the standard OP7 control panel (BT).

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

General Object of a Power Management System

The major task of the SIMOS PMA 71 power management system is to ensurethat adequate electrical power is provided for all the operating statesof the marine vessel. As the power demand on marine vessels increases,economic generation of power is, however, becoming virtually just asimportant as freedom from interruption.

The SIMOS PMA 71 automatic power generator system is based on therequirement of maintaining electrical power automatically during thevarious operating modes. In the event of faults in the on-board powersupply system, all the necessary measures are initiated in order tosupply the loads with electrical power with as little interruption aspossible, while at the same time preventing damage.

SIMATIC-S7 standard components are used for each machine unit, plus agenerator protection device/measurement transducer and an OC 24V/DC 24Visolating transformer. The generator protection device/measurementtransducer, DC 24V/DC 24V isolating transformer and SIMATIC S7 for eachindividual machine set controller form an independent system. Thisensures that only one machine unit is also affected if one system fails.

In addition to the 24V supply from the marine vessel's battery, thegenerator protection device has an internal voltage supply from thegenerator voltage. If the SIMATIC-S7 is likewise to be supplied by aredundant power supply, this must be provided by the switchgear assemblymanufacturer (for example a DC 24V power supply, fed from the busbarvoltage) in order that the operation of the PMA is ensured even if thehigher-level battery power supply fails.

The generator protection device can also be used on its own, withoutSIMATIC-S7, in which case it then provides only some of the functions(generator protection, synchronization). A PMA coupling switch, a PMAland connection and a PMA emergency diesel can be supplied in additionto the PMA generator. These have particular functions which differ fromthe PMA generator.

Some classification organizations require an additional, independentdiesel protection system (overspeed, lubricating oil pressure). The PMA71 diesel protection has only second-priority functions. The main dieselprotection is not part of the PMA 71.

Power and Functional Scope

-   -   On-board power supply system monitoring (black-out,        underfrequency, overfrequency, undervoltage, overvoltage)    -   Load-dependent starting of machine sets (overcurrent, overload)    -   Fault-dependent starting of machine sets    -   Overcurrents and reverse power protection of the generator    -   Disconnection of unimportant loads in three stages    -   Automatic stopping of machine units taking into account the        available power (underload)    -   Manual starting of machine sets (with two or more start        attempts, if set), and manual stopping (with previous reduction        in the load of the machine set, provided that another machine        set is also connected to the busbar)    -   Automatic synchronization of machine sets    -   Automatic regulation of the on-board power supply system        frequency    -   Automatic real load matching between the machine sets    -   Short-circuit protection    -   Fault indication integrated in the control panel    -   Load demand automatic system (option)

Special Features

-   -   High availability by structured design (fault in one PMA 71 does        not influence the operation of the other machine sets)    -   Simple servicing and fault localization by virtue of modular        design    -   Light-emitting diodes on all binary SIMATIC-S7 inputs and        outputs    -   Easy replacement of the assemblies in the SIMATIC-S7 by plug-in        technology    -   Easy matching of the system to different machine sets by way of        the generator protection device/measurement transducer    -   Little wiring complexity through the use of prefabricated        plug-in technology

General information:

Operational messages and fault messages are indicated on the controlpanel in the form of text.

Abbreviations may be necessary, depending on the space in the controlpanel display.

The type of message (operational or defect message) is shortened in thisdescription, in abbreviated form, using

BM (Operational message)

SM (Fault message)

The following abbreviations are used

DG (Diesel generator)

WG (Shaft generator)

HATA (Main switch panel)

B&B (Control and observation)

System Design

Individual Machine Set Components

The components of the SIMOS PMA 71 automatic power generator system areintended for decentralized installation using standard switch panels(associated with the generator panel) or for central installation instandard cabinets. For central installation, the generator protectiondevice must be installed in the respective generator panel, while theother components can be installed together, centrally, in one cabinet.

Each machine set has the following associated components, as standard:

-   -   Programmable logic controller (PLC, SIMATIC S7-300)    -   Generator protection/synchronization device/measurement        transducer (GENOP 71)    -   DC 24V/DC 24V isolating transformer    -   Control panel (OP).

If the PMA is installed in a central cabinet, then the GENOP 71generator protection device must be installed in the correspondinggenerator panel in the main switch panel. Other components can beinstalled in the central cabinet.

Plug Connections/Connections

Bus Couplings

The components of a machine set (PLC, GENOP 71, OP) are connected to oneanother via Profibus DP. The PLCs for the various machine sets areconnected via MPI coupling.

Peripherals

The external lines are connected via connecting modules (with screwconnections). The modules for digital output signals are fitted withrelays. (DC isolation between the output signals). These connectingmodules are connected to the input and output assemblies of theSIMATIC-S7 via front plugs and plug-in cables.

Generator Protection Device/Measurement Transducer

The following signals must be supplied to the generator protectiondevice/measurement transducer

3-phase generator voltage, (100V AC signal)

3-phase power supply system voltage, (100V AC signal)

one current transformer for each phase (1A AC signal)

These cables must be routed separately from the control cables (separatecable duct) within a cabinet or within a switch panel when they arelaid.

Shielding of the Cable and Lines

When laying signal lines and/or supply lines outside a cabinet/switchpanel, lines and cables which carry a voltage of 230 V or more must beseparated by a minimum distance of 10 cm.

FIG. 1 illustrates the system configuration.

Machine Set Control

The following operating modes are possible:

Local manual

Local semiautomatic

Automatic operation

Operation in the “Local Manual” Mode

The Local manual mode is normally selected for servicing tasks and forstarting and stopping machine sets “locally”. In this operating mode,the machine set is started and stopped with the PMA 71 being bypassed.The manual/automatic selector switch is switched to the “manual”position for switching.

The operating mode is indicated as “MANUAL” on the control panel.

The “manual/automatic” selector switch is arranged in the HATA.

In the Local manual mode, the automatic functions and operation via thecontrol panel are inhibited. The display functions are operative. Speedadjustments and the switching on of the generator switch can be carriedout only manually. The required devices for speed adjustment and controlof the generator switch must be supplied by the switch panelmanufacturer. Safety functions (disconnection in the event of overspeed,minimum lubricating oil pressure, maximum cooling water temperature etc.are still operative. When the generator switch is switched on, thegenerator protection is also operative.

Synchronization

Manual synchronization is carried out by way of a check synchronizationaid. Once the machine set has been started manually, the generatorfrequency is matched to the power supply system frequency by manualadjustment (from the switch panel). The “ENABLE KEY” must be pressed inorder to switch on the generator switch. The switch is switched on bythe synchronization aid at the next zero crossing. In the event of ablackout, the generator switch can be switched on directly by way of the“SWITCH ON” key.

Operation in the “Local Semiautomatic Mode”

Precondition: the “manual/automatic” selector switch is in the“automatic” position. Local semiautomatic is selected by pressing the“SEMI” key on the control panel. The operating mode is indicated as“SEMI” on the control panel. The following functions can be carried outfrom the control panel in the semiautomatic mode:

Starting of the machine

Stopping of the machine

Starting of synchronization

In order to avoid incorrect selections, additional confirmation with the“CONFIRM” key is required for important functions.

The safety functions (disconnection in the event of overspeed, minimumlubricating oil pressure, maximum cooling water temperature andgenerator protection) are operative. In the event of a fault, the dieselset is stopped as in the automatic mode, but no start command is issuedto the standby machine set.

Starting of the Machine Set

When the “START” key is operated, the “PRESS TO CONFIRM” message isdisplayed for an adjustable time on the control panel. However, thecommand is not carried out unless the “CONFIRM” acceptance key isoperated within this time. If this is not done, the request is rejected.

The start command can be given only if the motor is stationary, that isto say it has not reached self-sustaining speed and the generatorvoltage. If the “CONFIRM” key is operated during this time period, thestart command is given. At the same time, the BM “START VALVE” appearson the display. The start command is canceled by the signal“self-sustaining speed reached” or “generator voltage>85%”. The startcommand is given only for an adjustable time (start time).

The “self-sustaining speed” or “generator voltage>85%” signal results inBM “OPERATION” being displayed. If the “self-sustaining speed” or“generator voltage>85%” signal is not produced after two or more startattempts, then a further start command is issued.

Starting of Synchronization

The synchronization process can be carried out in two different ways:

without load distribution after synchronization

with load distribution after synchronization

Synchronization without Load Distribution

On operation of the “GEN. SWITCH ON” key, the “PRESS TO CONFIRM” messageappears on the control panel for an adjustable time. However, thecommand is not carried out unless the “CONFIRM” acceptance key isoperated within this time. If this is not done, the request is rejected.

The automatic synchronization process is now started, and the generatorswitch is switched on. The present mode of operation and the real powerbeing emitted from the machine set are now displayed on the controlpanel. No automatic load distribution is carried out. The loaddistribution can be changed manually.

Synchronization with Load Distribution

This function can be used only in the automatic mode. Operating the“AUTO” key results in a change to AUTO. After the change, the automaticsynchronization is started, and the generator switch is switched on.Automatic load adjustment starts after switching on.

Switching on the Generator Switch in the Event of a Blackout

In the event of a blackout, the generator switch is switched on asfollows:

by pressing the “GEN. Switch ON” key and “CONFIRM” or

by switching to automatic

Stopping the Machine Set

When the “STOP” key is operated, the “PRESS TO CONFIRM” message isdisplayed on the control panel for an adjustable time. However, thecommand is not carried out unless the “CONFIRM” acceptance key isoperated within this time. If this is not done, the request is rejected.

During parallel operation, a “Stop with load reduction” is carried outfirst of all. The BM “LOAD RED” is displayed. “Lower” adjustment pulsesare emitted until the machine set load has been reduced to below the“Gen Power Minimum” limit value. The generator switch is then switchedoff. When the generator switch has been switched off, the machine setcontinues to run for a certain time, for cooling. The “NO-LOAD RUN-ON”message is displayed on the control panel. Once the no-load run-on timehas elapsed, the machine set is stopped. When the stop command isemitted, the BM changes from “NO-LOAD RUN-ON” to “STOP”. Aftercompletion of the stop command, the machine set is ready to be startedonce again.

The “NO-LOAD RUN-ON” can be switched off (this is defined in theconfiguration section). In this case, the machine set is stoppedimmediately after the generator switch is switched off.

Switching off the Generator Switch

The operation of the “GEN. SWITCH OFF” key results in the “PRESS TOCONFIRM” message being displayed for an adjustable time on the controlpanel. However, the command is not carried out unless the “CONFIRM”acceptance key is operated within this time. If this is not done, therequest is rejected. In the parallel mode, a “Stop with load reduction”is carried out first of all. The BM “LOAD RED” is displayed. “Lower”adjusting pulses are emitted until the load on the machine set is belowthe “Gen. Power Minimum” limit value. The generator switch is thenswitched off.

Operation in the “Automatic Mode”

The automatic mode is selected by pressing the “AUTO” key on the controlpanel. The operating mode is displayed as “AUTO” on the control panel.

In the automatic mode, starting (standby start) and stopping (emergencystop, underload etc.) are carried out automatically or on request via acontrol and observation system.

Starting in the Automatic Mode

In the automatic mode, the starting process is initiated when themachine set is at “Standby” and a request is made by another machine setor by the higher-level control system.

The BM “START” appears on the display.

The start command is canceled in response to the “Self-sustaining speedreached” or “Generator voltage>85%” signal. The start command is issuedonly for an adjustable time (start time).

The “self-sustaining speed” signal results in the BM “OPERATION” beingdisplayed.

If the “self-sustaining speed” or “generator voltage>85%” signal is notproduced after two or more start attempts, then a further start commandis issued.

Stopping in the Automatic Mode

An undelayed stop command (emergency stop, short circuit, reverse poweretc.) results in the generator switch being switched off immediately. Ifthe machine set is stopped by an underload or by a remote stop via thecontrol and monitoring, and is being operated in the parallel mode, thena “Stop with load reduction” is carried out first of all.

The BM “LOAD RED” is displayed. “Lower” adjusting pulses are emitteduntil the load on the machine set has been reduced below the “Gen. PowerMinimum” limit value. The generator switch is then switched off. Whenthe generator switch is switched off, the machine set continues to runfor a certain time for cooling. The “NO-LOAD RUN-ON” message appears onthe control panel. Once the no-load run-on time has elapsed, the machineset is stopped. When the stop command is emitted, the BM changes from“NO-LOAD RUN-ON” to “STOP”. After completion of the stop command, themachine set is ready to be started again.

The “NO-LOAD RUN-ON” can be switched off (this is defined in theconfiguration section). In this case, the machine set is stoppedimmediately after switching off the generator switch.

Start Fault

The starting process with one or more starting attempts is the same inthe automatic and semiautomatic modes. If the “self-sustaining speed” or“generator voltage>85%” signal is not produced after two or more startattempts, then a stop command is issued. The following messages areissued:

“BLOCKED” (BM)

“START FAULT” (SM)

An additional command is issued in the automatic mode. Once the “STOP”command has disappeared, the defect message is acknowledged, and themachine set is ready to be started again. Resetting is not possible inthe automatic mode.

Adjustment of the Start and Stop Times

The start time, the pause time between the start attempts and the stoptime must be adjusted in accordance with the requirements for themachine set. The same time values are set for the automatic andsemiautomatic modes. The adjustment is carried out from a control panel.The number of start attempts can also be adjusted.

Standard settings: Start time  5 s Pause time  5 s Stop time 30 s Numberof start attempts  3

No-Load Run-on

A no-load run-on is recommended for some types of machine set in orderto cool the machine set before stopping it. The no-load run-on iscontrolled by the PMA 71. The control panel can be used to set the timefor which the no-load run-on is carried out. The no-load run-on isactive in the local semiautomatic mode and in the automatic mode. The BM“NO-LOAD RUN-ON” is displayed during this time.

Blocking of the Control Panel

Precondition:

Local semiautomatic mode

Machine set stationary

Blocking of the machine set is envisaged for servicing work. When the“ENTER” key is operated, the control menu is overlaid. The submenu“INPUT COMMANDS” is selected using the arrow key, a “1” is entered inthe “block machine set” field, and “ENTER” is pressed for confirmation.The display field can be reselected using the “ESC” key. The followingSM is displayed:

“CONTROL PANEL BLOCKING”

Reset Blocking

Select the submenu once again. Instead of “1”, now enter “0” and confirmwith “ENTER”. This resets the function.

Blocking Via a Blocking Switch

Most diesel sets have a “BLOCKED/LOCAL/REMOTE” selector switch, whichcan be switched over for servicing work. The selector switch must beswitched for PMA 71. The “BLOCKED/LOCAL” positions block any startcapability by the PMA 71. Depending on the selector switch position,either “BLOCKED” or “LOCAL” is displayed on the control panel.

However, the running machine set is not stopped. The monitoring for themachine set (overspeed, lubricating oil pressure, etc.) still remains inaction. If a start attempt is made in the local semiautomatic mode, thenthe following message appears on the control panel:

“MACHINE SET BLOCKED VIA BLOCKING SWITCH”

Acknowledgement of Alarm Messages

Alarm messages are displayed in blinking form in the lower two messagelines on the control panel, and they can be acknowledged using the “ACK”key. If the alarm message (for example an overvoltage) is no longercurrent, then it is deleted from the message buffer by operating the“ACK” key. If the message persists externally, then it changes from ablinking light to a continuous light on acknowledgement, and is stillindicated on the display. If the message disappears externally, then itis also deleted from the message buffer, and is no longer indicated onthe display.

Existing already acknowledged messages can be displayed using the ↑↓keys.

Resetting Blockings

Blockings of the machine set (for example initiated by an overspeed or ashort circuit on the busbar etc.) are displayed on the control panel byway of the “BLOCKED” operating message, and must be reset by operatingthe “CONFIRM” key. Resetting can be carried out only when the machineset is stationary.

Initial Lubrication

The PMA 71 provides one output (floating contact) for controlling theinitial lubrication. The following functions can be set on the controlpanel.

No initial lubrication

Continuous initial lubrication

Cyclic initial lubrication

Initial lubrication before start

It is also possible to select whether initial lubrication should becarried out in the standby mode, in the automatic mode, or in theautomatic mode and in the local semiautomatic mode.

Continuous Initial Lubrication

If this function is selected, the machine set will be initiallylubricated continuously as long as it is not running.

The initial lubrication process is started when the “self-sustainingspeed” and “generator voltage>85%” signals have disappeared. The initiallubrication process ends when the “self-sustaining speed” or “generatorvoltage>85%” signals appear.

If the blocking switch is inserted on the machine set, the initiallubrication is switched off.

Cyclic Initial Lubrication

When this function is selected, the machine set is initially lubricatedcyclically, for as long as it is not running.

The times can be set on the control panel.

Standard settings: Initial lubrication time 2 min Pause time 2 hours

The initial lubrication is started when the “self-sustaining speed” and“generator voltage>85%” signal have disappeared. The initial lubricationprocess ends when the “self-sustaining speed” or “generator voltage>85%”signals appear. If the blocking switch is inserted on the machine set,then the initial lubrication is switched off.

Initial Lubrication Before Start

This function provides initial lubrication for the machine set for anadjustable time, with the machine set then being started. However, thetime that has passed since the last initial lubrication was carried outis checked. If the time is too long, initial lubrication is carried out.If the time is shorter than set, starting is carried out immediately.The times can be set on the control panel.

Standard settings: Initial lubrication time 30 s Longest time for startwithout  5 min initial lubrication

A start without initial lubrication is carried out in the event of a“Blackout”.

Initial Lubrication Monitoring (Option)

A contact from an external initial lubrication system is required forthis function. The alarm is evaluated with a delay. Once the delay timehas elapsed, the machine set is blocked. The delay time can be set onthe control panel.

The following messages are output on the control panel:

“BLOCKED” (BM) “LUBRICATING OIL PRESSURE FAULT” (SM)

Blocking is active in the automatic mode and in the local semiautomaticmode. Resetting is usually impossible as long as the alarm is active.The alarm is suppressed in the event of a “Blackout”.

Preheating

The PMA 71 has one output (floating contact) for controlling thepreheating. It is possible to select whether the initial lubricationshould be carried out in the standby mode, in the automatic mode or inthe automatic mode and in the local semiautomatic mode.

The preheating is started when the “self-sustaining speed” and“generator voltage>85%” signals have disappeared. The preheating endswhen the “self-sustaining speed” or “generator voltage>85%” signalsappear. If the blocking switch is inserted on the machine set, then thepreheating is switched off.

Slow Turn (Option)

This function slowly rotates the crankshaft of the diesel set, and thenstarts it. However, the time which has passed since the machine set waslast started is checked. If the time is too long, slow turning iscarried out. If the time is shorter than set, starting is carried outimmediately. The time can be set on the control panel.

Standard settings: Time for slow turn 10 s Longest time for startwithout  2 hours slow turn

Starting is carried out without any slow turn in the event of a“blackout”.

“Self-Sustaining Speed” Signal

The PMA 71 requires the “self-sustaining speed” (self-sustainingspeed=contact closed) signal for various functions. The speed detection(for example a speed relay) is not part of the PMA 71.

Safety Functions

The PMA 71 allows safety functions to be provided. Four digital inputswith wired discontinuity monitoring can be used as standard. Normally,these are used as follows:

No. 1: “Overspeed” No. 2: “Minimum lubricating oil pressure” No. 3:“Maximum cooling water temperature” No. 4: Spare (for example “Minimumcooling water pressure”)

Further inputs may optionally be provided.

The machine set must be equipped with appropriate sensors. For wirediscontinuity monitoring, each sensor contact is bridged by a 5.6kiloohm resistor. The PMA 71 identifies the resistance as follows:

Resistance ~8 kΩ (Wire discontinuity Wire or no resistor indiscontinuity parallel): Resistance ~5.6 kΩ (Contact open with No stopresistor in parallel): Resistance ~0 (Contact closed): Undelayed stopIn order to prevent initiation by short interference pulses, the alarms2 . . . 4 are provided with a delay time. This time can be selected fromthe control panel. The standard setting is one second. When one of thesealarms occurs, the machine set is stopped and blocked immediately. Inthe automatic mode, a standby machine set is started.

The following messages are displayed on the control panel:

“BLOCKED” (BM)and the corresponding reason message:

“OVERSPEED” (SM) or “MINIMUM LUBRICATING OIL PRESSURE” (SM) or “HIGHCOOLING WATER TEMPERATURE” (SM) or “ALARM NO. 4” (SM)

Undelayed Stop/Delayed Stop

The safety disconnection can be delayed or undelayed. The maximumcooling water temperature criterion, for example, requires eitherundelayed or delayed disconnection depending on the machine set type(this is defined in the configuration section). If delayed disconnectionis provided, then the BM “DELAYED STOP” is first of all output on thecontrol panel if the cooling water temperature is exceeded. Once a delaytime has elapsed, the machine set is then stopped. The delay time can beset on the control panel.

Speed/Time-Dependant Enabling of the Alarms

When the machine set is not running, some values (for examplelubricating oil pressure) will be below the alarm point. Whilst themachine set has been started, these values require some time to reach anormal level. For this reason, the alarms can be blocked until a delaytime has elapsed. (Delay time 1 or delay time 2). Alarm No. 2(lubricating oil pressure) is blocked until the delay time 1 haselapsed.

Standard settings: Monitoring time 1 15 s Monitoring time 2 45 sThe monitoring time 1 is started by the “self-sustaining speed” or“generator voltage>85%” signals. Once this time has elapsed themonitoring time 2 is started.

Alarm Blocking

One floating contact is available for alarm blocking. This output isactive when the machine set is not running, and until the monitoringtime 1 has elapsed after starting of the machine set. This signal makesit possible to block alarms from an external alarm system whenstationary or while the machine set is running up.

Emergency Stop

A digital input is provided for the emergency stop function. An“emergency stop” pushbutton can be connected here. This functioninitiates an immediate stop, and blocking of the machine set. Thefunction is active in the automatic mode and in the local semiautomaticmode, but only when the machine set is running, for example when thesignals “self-sustaining speed” or “generator voltage>85%” are present.

The following messages are displayed on the control panel:

“BLOCKED” (BM) “EMERGENCY STOP” (SM)

The “emergency stop” function does not initiate a standby start. Itshould be remembered that emergency stopping of a machine set can causea blackout when the corresponding machine set is the only one connectedto the power supply system, or when the remaining machine set isoverloaded. For safety reasons, the emergency stop valve should also beoperated directly, bypassing the PMA 71.

Emergency Stop Valve

Some machine sets also have an emergency stop valve in addition to thenormal stop valve. This valve is operated when the machine set isintended to be stopped as quickly as possible (undelayed stop, emergencystop, short circuit, etc.). The PMA 71 has one output for operating thisvalve.

Suppression Valve

The PMA 71 provides one output for operating a suppression valve. Thisvalve is operated when the machine set is not running, and isdeactivated with a delay by the “self-sustaining speed” or “generatorvoltage>85%” signals. The delay time can be set on the control panel.

Initial Alarm (Option)

Precondition:

Automatic Mode

This function is required to start a standby machine set as aprecaution, in order to prevent an undelayed stop being required. Thesignal can come directly from the machine set as an initial alarm, or asa group alarm from the alarm system. (For example, initial alarm aslubricating oil pressure and cooling water temperature). The controlpanel can be used to select whether the faulty machine set should bestopped (with a previous load reduction), or should remain connected tothe power supply system.

The following messages are displayed on the control panel:

“INITIAL ALARM” (BM)

The message is acknowledged by operating the “RESET” key.

Remote Control

If the PMA 71 is connected to a higher-level control and observationsystem, then the following control actions are possible:

Start the machine set

Stop the machine set

Activate/deactivate the connection and disconnection chain

Activate/deactivate the UBL mode

Connect/disconnect the land connections

Connect/disconnect the coupling switches

Furthermore, the actual values such as the machine set real power,currents, voltages and frequency are provided and can be processedfurther in a standard data module. In order to transfer the controlauthorization to the control and monitoring system, the “remote” keymust be operated on the OP 7.

The operating mode is displayed as “REMOTE” on the control panel. The OP7 cannot be used for control purposes during remote control. The “semi”or “automatic” key must be operated in order to switch control back tothe OP 7. Further information can be found in the operating instructionsfor the appropriate control and monitoring system.

Control of Shaft Generators

General Note:

The description covers only control of the WGA 23D and the conventionalWG.

WGA 23D

The WGA 23D is a shaft generator control system comprising a shaftgenerator, a static converter and a wattless component machine. Theconverter is used to convert the frequency of the shaft generator to thebusbar frequency. This can be done within a range from 40% to 100% ofthe machine speed. Parallel operation between the WGA and dieselgenerators is possible.

The WGA 23D is used in marine vessels with fixed-pitch propellers andvariable-pitch propellers. For marine vessels with fixed-pitchpropellers, the speed of the vessel can be controlled only via the speedof the main machine. For vessels with variable-pitch propellers, thespeed of the vessel is regulated by the speed of the main machine and bythe propeller pitch. The WGA 23D thus allows shaft generator operationover a wide speed range.

Standard values: Speed of the main machine WGA 23D power margin 100% →75% 100%  75% → 40% 100% → 50%

WG Control Via Epicyclic Gearing (for Example Renck)

In this case, the shaft generator is coupled to the main machine viaepicyclic gearing. Once again, continuous parallel operation is possiblein this case, in the range from 70% to 100% of the machine speed.

The generator frequency is in this case matched to the main machinespeed via the gearing.

Conventional Shaft Generator (PTO)

This control system is used predominantly for marine vessels withvariable-pitch propellers, since the shaft generator frequency is keptconstant by switching the main machine to constant speed. The speed ofthe vessel is in this case regulated by varying the propeller bladepitch. Parallel operation between WG and DG is feasible only for loadtransfer or in an extremely calm sea.

WGA 23D

Switching on the WGA 23D

The WGA 23D can be switched on only when the on-board power supplysystem is available. Blackout starting, as in the case of DG is notpossible. The WGA 23D is switched on from the PMA 71 control panel inthe local semiautomatic mode. A number of preconditions have to besatisfied before the WGA 23D can be switched on.

The speed of the main machine is in the operating range

The coupling must be switched on

The WGA control is switched on

No fault message in the control system

If these preconditions are satisfied, then the WGA 23D passes the “READYTO START” signal to the PMA 71. The following message is displayed onthe control panel:

“START” (BM)

When the “START” key is operated the “PRESS TO CONFIRM” message isdisplayed on the control panel for an adjustable time. However, thecommand is not carried out unless the “CONFIRM” acceptance key isoperated within this time. If this is not done, the request is rejected.A start command can be issued only when the “READY TO START” signal fromthe WGA 23D is present. If the “CONFIRM” key is operated within thistime, then a start command is issued to the WGA 230 controller. The WGA23D now starts the start-up process. The following message is displayedon the control panel:

“OPERATION” (BM)

The generator voltage>85% signal results in the message

“OPERATION” (BM)

being displayed.

After completion of the start-up process (after approximately 60seconds) the “ready for synchronization” and “enable generator switch”signals are passed from the WGA 23D to the PMA 71. The followingmessages are displayed on the control panel:

“READY FOR SYNCHRONIZATION” (BM) “ENABLE GENERATOR SWITCH” (BM)

If the PMA 71 is switched to “automatic”, the synchronization is startedThe paritetic load distribution is carried out once the generator switchhas been switched on.

The currently active operating state and the real power being emittedfrom the generator are displayed on the control panel. The “ENABLEGENERATOR SWITCH” signal is wired directly to the main switch panel. Thegenerator switch cannot be switched on without this signal. The WGA 23Dcan switch off the generator switch by canceling this signal (in theevent of a serious fault).

Start Fault

If the “ENABLE GENERATOR SWITCH” signal does not arrive within aspecific time after the start command has been issued, the followingmessage appears on the control panel:

“START FAULT” (FM)

Manually Switching Off the WG in the Parallel Mode

The WGA 23D can be stopped from the PMA 71 control panel in the localsemiautomatic mode. When the “STOP” key is operated, the “PRESS TOCONFIRM” message is displayed on the control panel for an adjustabletime. However, the command is not carried out unless the “CONFIRM”acceptance key is operated within this time. If this is not done, therequest is rejected.

A stop command is passed to the WGA 23D controller. If the machine setis being operated in parallel on the power supply system, then a “STOPwith load reduction” is carried out first.

The BM “LOAD RED” is displayed on the control panel. “LOWER” adjustingpulses are emitted in order to reduce the load on the machine set. Thegenerator switch is switched off when the power falls below the “GEN.POWER MIN.” limit value. Once the generator switch has been switchedoff, a “STOP” command is passed to the WGA 23D controller.

When the “STOP” command is output, the operation message on the controlpanel changes from “LOAD RED” to “MACHINE SET STOPPING”.

Manually Switching Off the WG in the Insular Mode

If the WG is the only one connected to the power supply system, thenswitching it off would result in a blackout. A diesel set must thereforebe started and synchronized before this is done. After synchronizationof the DG, the rest of the process is as described previously.

Slow Down of Main Machine

The PMA 71 is supplied with this signal via a floating contact from thediesel remote control. In the event of a slow down, the speed of themain machine is maintained by the remote control for a certain time inorder to start a standby machine set and to carry out a load transfer.

When this signal arrives, the PMA 71 is blocked and a standby machineset is started. The following message is displayed on the control panel:

“SLOW DOWN OF MAIN MACHINE”

After starting and synchronization of the standby machine set, the PMA71 controller for the WGA 23D carries out a “stop with load reduction”.“LOWER” adjusting pulses are emitted in order to reduce the load on themachine set. During the process of reducing the load, the BM “LOAD RED”is displayed on the control panel. When the power falls below the limitvalue “GEN. POWER MIN.”, the generator switch is switched off.

When the generator switch is switched off, the PMA controller for theWGA 23D is switched to the “local semiautomatic mode”. At the same timea “STOP” command is passed to the WGA 23D controller. When the “STOP”command is issued, the operation message changes from “LOAD RED” to“STOP”.

When the generator switch is switched off, the remote control continueswith the “slow down” of the main machine. A floating contact must beconnected from the switch panel to the diesel remote control for thisfunction (this is not a function of the PMA 71).

Shut Down of the Main Machine

The PMA 71 is supplied with this signal via a floating contact from thediesel remote control. In contrast to the “slow down of the mainmachine”, the speed of the main machine is in this case not maintainedfor a specific time. The rate of change of speed of the main machinedetermines whether there is sufficient time to start a standby machineset, and to carry out a load transfer. Normally, a shut down of the mainmachine leads to a blackout.

The signal results in a start command being issued to the standbymachine set, and in the WGA 23D controller being blocked. If the “starttwo generators in the event of a fault” function is selected, then twodiesel sets are started.

The following message:

“EMERGENCY STOP OF MAIN MACHINE”

is displayed on the control panel.

After starting and synchronization of the standby machine set, the PMA71 controller for the WGA 23D carries out a “stop with load reduction”.“LOWER” adjusting pulses are emitted in order to reduce the load on themachine set. During the load-reduction process, the BM “LOAD RED” isdisplayed on the control panel. When the power falls below the “GEN.POWER MIN.” limit value, the generator switch is switched off.

When the generator switch is switched off, the PMA controller for theWGA 23D switches to the “local semiautomatic mode”. At the same time, a“STOP” command is passed to the WGA 23D controller. When the “STOP”command is issued, the operation message changes from “LOAD RED” to“STOP”.

If the speed of the main machine falls below the operating range of theWGA 23D before the load transfer has taken place to the standby machineset, then the generator switch is switched off by the WGA 23Dindependently of the PMA 71. The standby machine set that has alreadystarted is then connected via “blackout”.

Machine Telegraph (MT)<n_(Min)

The PMA 71 is supplied with this signal via a floating contact eithervia the diesel remote control or from the WGA 23D. The minimum speed foroperation of the WGA 23D is normally 40% of the rated speed of the mainmachine. The minimum speed is, however, dependent on the design of themain machine and of the WGA 23D. If the MT lever is set below thislimit, the diesel remote control stops the reduction in the speed atthis point in order to allow a standby machine set to be started and aload transfer to be carried out.

If this signal occurs in the automatic mode when the generator switch isclosed, a standby machine set is started. The following message isdisplayed on a control panel:

“MT < N MIN” (BM)

After starting and synchronization of the standby machine set, the PMA71 controller for the WGA 23D carries out a “STOP WITH LOAD REDUCTION”.“LOWER” adjusting pulses are emitted in order to reduce the load on themachine set. During the load-reduction process, the BM “LOAD RED” isdisplayed on the control panel. When the power falls below the “GEN.POWER MIN.” limit value, the generator switch is switched off.

Once the generator switch has been switched off, the diesel remotecontrol continues to reduce the speed. A floating contact must be passedfrom the switch panel to the diesel remote control for this function(this is not a function of the PMA 71)

Machine Telegraph (MT)>n_(Min)

If the MT lever is once again set to a value above the minimum speed,the “STOP WITH LOAD REDUCTION” function is canceled. The BM “LOAD RED”which may already be displayed on the control panel is extinguishedagain. The machine set that has already been started is synchronized,and is stopped once again if the load is too low, or manually.

DG Request (Warning)

The PMA 71 is supplied with this signal via a floating contact from theWGA 23D. The signal is produced when the WGA 23D detects an overload. Astandby machine set is started.

The following message is displayed on the control panel:

“DG REQUEST FROM THE WG” (BM).

Load sharing is carried out after starting and synchronization of thestandby machine set.

WG Delayed Stop

The PMA 71 is supplied with this signal via a floating contact from theWGA 23D. If the WGA 23D has identified a fault which still allowsoperation to continue for a short time, then the “WG DELAYED STOP”signal is passed to the PMA 71. Normally, this time is sufficient tostart a standby machine set and to carry out a load transfer.

When this signal arrives, a delayed stop of the WGA 23D is carried out,together with blocking of the controller, and a standby machine set isstarted. The following message is displayed on the control panel:

“WG DELAYED STOP”.

Once the standby machine set has been started and synchronized, the PMA71 controller for the WGA 23D carries out a “stop with load reduction”.“LOWER” adjusting pulses are emitted in order to reduce the load on themachine set. During the load-reduction process, the BM “LOAD RED” isdisplayed on the control panel. When the power falls below the “GEN.POWER MIN.” limit value, the generator switch is switched off.

When the generator switch is switched off, the PMA controller for theWGA 23D is switched to the “local semiautomatic mode”. At the same timea “STOP” command is passed to the WGA 23D controller. When the “STOP”command is output, the operation message changes from “LOAD RED” to“STOP”.

WG Undelayed Stop

The PMA 71 is supplied with this signal via a floating contact from theWGA 23D.

If the WGA 23D has identified a critical fault which requires animmediate stop, then this signal is passed to the PMA 71. The WGA 23D isde-energized, and the generator switch is switched off. (“Enablegenerator switch” signal=Off). If the shaft generator is connected tothe power supply on its own, then this signal causes a blackout.

When this signal occurs, an undelayed stop of the WGA 23D is carriedout, the generator switch is switched off, the controller is blocked anda standby machine set is started. The following message is displayed onthe control panel:

“WG UNDELAYED STOP”.

If the PMA 71 was in the automatic mode, then it is switched to thelocal semiautomatic mode.

In the event of a blackout, the newly started standby machine set isconnected after a short run-up time, or it is synchronized if anothermachine set perfume to the power supply system.

Reverse Power Protection for the WGA 23D

Reverse power protection for the shaft generator is not necessary, sincethe WGA 23D does not allow any reverse power flow. However, a small realpower flow to the WGA 23D is required in order to operate the wattlesscomponent machine when the shaft generator is running on no load. Inorder to prevent the generator switch from being switched off, thereverse power protection for the shaft generator should be switched off,or the limit value should be set sufficiently high that it cannot betriggered.

Conventional WG (PTO)

The frequency of the shaft generator is dependent on the speed of themain machine. Any change in the speed (for example resulting from aheavy sea) also changes the frequency of the on-board power supplysystem. During parallel operation with a diesel generator, this leads tosevere load shifts. For this reason, PMA 71 does not allow continuousparallel operation between SG and DG.

Switching on the WG when the on-Board Power Supply is Present

The function described here carries out a load transfer from a DG to aWG. The main machine is switched to constant speed by supplying onecontact to the remote control for this purpose. When the contact isswitched on, the remote control keeps the main machine at a constantspeed. When the WG is switched on, the remote control receives the “WGON” signal. However, the speed can now be reduced only if the WG haspreviously been switched off again and the “WG ON” signal hasdisappeared.

The following conditions must be satisfied in order to switch on the WG:

Generator voltage greater than 85%

READY TO SWITCH ON signal

The following BMs are displayed on the control panel

SEMI

READY TO SWITCH ON.

Switch to AUTOMATIC.

When the automatic mode is switched on, the WG controller passesadjusting pulses to the diesel set via the connection for commonfrequency adjustment, in order to match the frequency of the on-boardpower supply system to its own frequency (this works only when READY TOSWITCH ON is present). Synchronization is carried out as for a dieselset. After synchronization, the DG receives LOWER adjusting pulses fromthe WG controller and reduces the load on the DG.

During the load-reduction process, the BM LOAD RED is displayed on thecontrol panel. Once the power falls below the “Gen. power minimum” limitvalue, the generator switch is switched off. The DG can still carry outa no-load run (depending on the configuration) and is then stopped. Whenthe stop command is emitted, the BM LOAD RED is extinguished.

Switching Off the WG

The function described here carries out a load transfer from SG to a DG.In order to switch off the WG, a DG is started in the localsemiautomatic mode. After switching to AUTOMATIC, the synchronization ofthe DG is started. After switching on the generator switch, a “stop withload reduction” is carried out for the WG. During the load reductionprocess, the BM “LOAD RED” is displayed on the ST.

The WG controller passes adjusting pulses to the diesel set via aconnection between the PMA 71 systems. “High” adjusting pulses arepassed to the DG until the load on the WG is reduced below the“Generator power minimum” limit value. The generator switch is thenswitched off. When the generator switch is switched off, the BM “LOADRED” is extinguished, and the WG controller is switched to the localsemiautomatic mode.

Slow Down of Main Machine

The PMA 71 is supplied with this signal via a floating contact from thediesel remote control. In the case of a slow down, the speed of the mainmachine is maintained by the remote control for a certain time in orderto start a standby machine set and to carry out a load transfer.

When this signal occurs, a delayed stop of the WG, blocking of thecontroller and starting of a standby machine set are carried out. Thefollowing message is displayed on the control panel:

“SLOW DOWN OF MAIN MACHINE” (SM).

After the DG has been started and synchronized a “Stop with loadreduction” is carried out for the WG.

During the load-reduction process, the BM “LOAD RED” is displayed on theST. The WG controller passes adjusting pulses to the diesel set via aconnection between the PMA 71 systems. “Higher” adjusting pulses arepassed to the DG until the WG load has been reduced below the “Generatorbreaker minimum power” limit value. The generator switch is thenswitched off.

When the generator switch is switched off, the BM “LOAD RED” isextinguished, and the BM “BLOCKED” is displayed. The WG controller isswitched to the local semiautomatic mode.

After switching off the generator switch, the remote control continuesthe slow down of the main machine. A floating contact must be passedfrom the switch panel to the diesel remote control for this function(that is not the function of the PMA 71).

Emergency Stop of Main Machine, Delayed/Undelayed Step of the WG

The PMA 71 is supplied with this signal via a floating contact from thediesel remote control. In contrast to the “Slow down of main machine”,the speed of the main machine is in this case not maintained for aspecific time. The rate of change of speed of the main machinedetermines whether there is sufficient time to start a standby machineset, and to carry out a load transfer.

The signal results in a start command being passed to the standbymachine set, and the WGA 23D controller being blocked. If the function“start two generators in the event of a fault” is selected, then twodiesel sets are started. The following message is displayed on thecontrol panel:

“EMERGENCY STOP OF MAIN MACHINE”.

Once the DG has been started and synchronized, a “Stop with loadreduction” is carried out for the WG.

During the load-reduction process, the BM “LOAD RED” is displayed on thecontrol panel. The WG controller passes adjusting pulses to the dieselset via a connection between the PMA 71 systems. “Higher” adjustingpulses are passed to the DG until the load on the WG has been reducedbelow the “Generator breaker minimum power” limit value. The generatorswitch is then switched off.

When the generator switch is switched off, the BM “LOAD RED” isextinguished, and the BM “BLOCKED” is displayed. The WG controller isswitched to the local semiautomatic mode.

If the speed is already below the operating range of the WG (Generatorswitch trips due to undervoltage or underfrequency), the standby machineset which has already been started is connected via “blackout”.

Reverse Power

While the load is being accepted or transferred, the DG can change toreverse power mode due to severe speed fluctuations in the main machine(because of the marine vessel's propeller surfacing due to the waveheight, etc.). Reverse power evaluation of the DG is therefore inhibitedduring this time. Reverse power evaluation is generally inhibited forthe WG, since it always runs on its own.

On-Board Power Supply System Monitoring

The on-board power supply system monitoring has the following tasks:

-   -   Start of a standby machine set in the event of a blackout, in        order to supply the loads with electrical power as quickly as        possible once again,    -   Protection of the on-board power supply system against        unacceptable frequency errors (underfrequency), by switching off        unimportant loads,    -   Protection of the on-board power supply system against        unacceptable frequency disturbances        (underfrequency/overfrequency) by switching off the generator        switch. If there is a major difference between the busbar        frequency and the rated frequency, synchronization is often        impossible, because the rated frequency is outside the        adjustment range of the speed adjustment device. Switching is        therefore carried out via “blackout”.    -   Protection of the on-board power supply system against        unacceptable voltage discrepancies (undervoltage/overvoltage) by        switching off the generator switch. In this case, no paralleling        is carried out, since the different magnitudes of the voltage        that is set on the busbar and the voltage that is set on the        generator that is to be connected would result in a high        reactive current flowing. For this reason, switching takes place        via a “blackout”.

Blackout

Busbar monitoring (for example two auxiliary contactors) must beprovided by the switch panel manufacturer. These auxiliary contactorscan be connected between the phases L1–L2, L2–L3 via a circuit breaker.Each relay requires two auxiliary contacts (1M, 1B), and the circuitbreaker requires one auxiliary contact (1B). These auxiliary contactsmust be connected such that two signals are provided for the PMA 71.

a) Blackout signal (all auxiliary contactors tripped, B, circuitbreaker, M)

b) “Busbar voltage present” signal (all auxiliary contactors connected,M)

This circuit ensures that no blackout is identified as a result of thedisconnection of the circuit breaker or as a result of the failure ofone of two phases. The following message is displayed on the controlpanel:

“BUSBAR MONITORING FAULT” (SM)

The busbar monitoring must be provided separately for each PMA 71. Theauxiliary relay contacts are connected to the corresponding connectionsof the PMA 71.

If “BLACKOUT” is identified, then the next available machine set isstarted, and is switched on following a short delay time after thegenerator voltage reaches>85%. Simultaneous connection of the generatorswitches for two or more machine sets which are started at the same timeto the non-live busbar is prevented by way of a simultaneous inhibit

Underfrequency/Overfrequency

Automatic Mode

The frequency of the on-board power supply system is detected via thegenerator protection device/measurement transducer, and is monitored inthe SIMATIC-S7. The limit values and delay times forunderfrequency/overfrequency can be changed from the control panel. Thefunction is password-protected.

The following messages are output if the respective limit values areundershot or exceeded:

“Overfrequency”

“Underfrequency 1”

“Underfrequency 2”

“Underfrequency 3”

The initiated functions are listed in the “GENERATOR PROTECTION” table.

Local Semiautomatic Mode

If a machine set is being used in the manual mode and an underfrequencyor overfrequency is identified, then the messages which are produced areas described above, although no machine set is added.

Undervoltage/Overvoltage

Automatic Mode

The frequency of the on-board power supply system is detected via thegenerator protection device/measurement transducer, and is monitored inthe SIMATIC-S7. The limit values and delay times forunderfrequency/overfrequency can be changed from the control panel. Thefunction is password-protected.

The following messages are output if the respective limit values areundershot or exceeded:

“Overvoltage”

“Undervoltage 1”

“Undervoltage 2”

“Undervoltage 3”

The initiated functions are listed in the “GENERATOR PROTECTION” tablein Section 7.

Local Semiautomatic Mode

If a machine set is being used in the manual mode and an underfrequencyor overfrequency is identified, then the messages which are produced areas described above, although no machine set is added.

Generator Protection

The generator protection has the following tasks:

-   -   Protection of the generator and of the on-board power supply        system against the consequences of a short circuit, by        disconnection of the generator switches for the generators which        feed the on-board power supply system. In this case, the        disconnection normally takes place with a short time delay, in        order to provide time for lower-level circuit breakers to be        disconnected (selectivity).    -   Short-circuit counting, stopping and blocking of the machine set        and switching of the other machine sets to manual operation, in        order to prevent automatic connection of a standby generator to        the busbar.    -   If appropriate, allowing standby start and connection of the        generator to the busbar (thus, a second short circuit if the        short circuit has not been rectified in the meantime).    -   Protection of the generator against overloading due to        disconnection of the generator switch when an overcurrent is        flowing.    -   Protection of the generator against overloading due to        disconnection of unimportant loads when overcurrent is flowing,        overloading.    -   Disconnection of the generator switch in the event of reverse        power.    -   In addition, undelayed short-circuit tripping for very large        short-circuit currents, or differential protection, is also        required. These functions are not included in the PMA 71 but        need to be provided separately in the switchgear assembly.

Short Circuit

The generator currents are monitored for short circuits by the generatorprotection apparatus/measurement transducer GENOP 71. If a short circuitoccurs, the output relay for the generator switch is operated. In orderto achieve selectivity between the generator switch and the lower-levelcircuit breakers, the generator switch is normally switched off with adelay.

The limit value and the delay time can be set via the control panel. Thefunction is password-protected.

A stock command is emitted to the relevant diesel engine (or to theshaft generator controller). The following messages are displayed on thecontrol panel:

“GENERATOR SHORT CIRCUIT” (SM) “BLOCKED” (BM)

The following message is displayed on the control panel of the othermachine set:

“OTHER MACHINE SET SHORT CIRCUIT” (SM)

It is possible to select whether one or two short circuits is or areallowed.

If only one short circuit is allowed, all the other machine sets areswitched to “semiautomatic” after just one short circuit. The othermachine sets do not start.

If two short circuits are allowed, one standby machine set is startedand connected to the power supply system after the first short circuit.If a second short circuit occurs, this machine set is also stopped andblocked and all the other machine sets are switched to “semiautomatic”.This prevents a third machine set from being started and connected.

The off command for the generator switch is provided directly from thegenerator protection device/measurement transducer, and still operateseven in the event of failure of the PLC or of the 24V DC supply voltage(for supplying the generator protection device from the generatorvoltage). The other functions are carried out in the PLC.

Short-Circuit Acknowledgement

The short-circuit storage for that particular machine set must beacknowledged manually. Once the stop command has disappeared, theblocking of the machine set can be canceled.

Overcurrent

The three generator currents I_(L1)/I_(L2)/I_(L3) are monitored in thegenerator protection device/measurement transducer for exceeding variouslimit values. If at least one of the currents exceeds the limit value,unimportant loads and/or the generator switches are disconnected oncethe delay time has elapsed. The limit values and delay times can bevaried via the control panel. The function is password-protected.

The following signals are emitted:

Disconnection of unimportant loads, level 1

Disconnection of unimportant loads, level 2

Disconnection of unimportant loads, level 3

Disconnection of generator switches

Machine set stop command

Block machine set

Switching to semiautomatic

The association between the individual functions and the limit values aswell as the standard settings are shown in Table 7.8.

Depending on the function that is initiated, the following messages aredisplayed on the control panel:

“DISCONNECTION OF UNIMPORTANT LOADS 1” (SM) or “DISCONNECTION OFUNIMPORTANT LOADS 2” (SM) or “DISCONNECTION OF UNIMPORTANT LOADS 3” (SM)or “OVERCURRENT, STANDBY START” (SM) “BLOCKED” (BM) “SEMI” (BM)“Generator switch case” (SM)

The off command for the generator switch and for the unimportant loadscomes directly from the generator protection device/measurementtransducer, and still works even in the event of failure of the PLC orof the 24V DC supply voltage (the supply for the generator protectiondevice from the generator voltage). The other functions are carried outin the PLC.

Overload

The emitted power from the generator is detected in the GENOP 71generator protection device, and is monitored in the Simatic-S7. Thelimit values for overloading can be varied from the control panel. Thefunction is password-protected.

The following signals are emitted:

Disconnection of unimportant loads, level 1

Disconnection of unimportant loads, level 2

Disconnection of unimportant loads, level 3

Disconnection of generator switches

Machine set stop command

Block machine set

Switching to semiautomatic

The association between the individual functions and the limit values aswell as the standard settings are shown in Table 7.8.

Depending on the function that is initiated, the following messages aredisplayed on the control panel:

“DISCONNECTION OF UNIMPORTANT LOADS 1” (SM) or “DISCONNECTION OFUNIMPORTANT LOADS 2” (SM) or “DISCONNECTION OF UNIMPORTANT LOADS 3” (SM)or “OVERCURRENT, STANDBY START” (SM) “BLOCKED” (BM) “SEMI” (BM)“Generator switch case” (SM)

The off command for the generator switch and for the unimportant loadscomes directly from the generator protection device/measurementtransducer, and still works even in the event of failure of the PLC orof the 24V DC supply voltage (the supply for the generator protectiondevice from the generator voltage). The other functions are carried outin the PLC.

Monitoring of the Current Transformers

The current transformers are monitored when the generator switch isswitched on. This is done by comparing the mean value with the extremevalue. The following states result in a fault message:

-   -   Extreme value (greatest value of the three generator currents        (I_(L1)/I_(L2)/I_(L3)) less than the mean value    -   Mean value less than 75% of the extreme value

When a fault occurs, the following message is displayed on the controlpanel:

“FAULT IN CURRENT MEASUREMENT” (SM)

This monitoring presupposes that the single-phase on-board power supplysystem loads are shared in a largely balanced manner. This makes itpossible to identify faults in the current transformer and a wirediscontinuity in the current transformer circuit.

The function can be switched off via the control panel.

Reverse Power

The real power is monitored in the generator protectiondevice/measurement transducer. If the reverse power limit value isexceeded, the generator switch is disconnected once a delay time haselapsed. The limit value and the delay time can be varied via thecontrol panel. The function is password-protected.

The following signals are emitted:

Disconnection of generator switches

Machine set stop command

Block machine set

Switch to local semiautomatic mode

Request standby machine set

The following messages are displayed on the control panel:

“REVERSE POWER” (SM) “BLOCKED” (BM)

The limit value and the delay time can be varied via the control panel.The function is password-protected. The standard settings are shown inTable 7.8.

The off command for the generator switch comes directly from thegenerator protection device/measurement transducer, and still operateseven in the event of failure of the PLC or of the 24V DC supply voltage.The other functions are carried out in the PLC.

External Generator Protection

Some of the generator protection functions described above are alreadyintegrated in the generator switch, or in the switch panel. In order toavoid duplicated tripping with virtually the same limit values from twodifferent gradients, the relevant limit values in the PMA could in thiscase be set sufficiently high that tripping is carried out only by thegenerator protection in the switch panel. The other functions (standbystart, fault signaling, etc.) which are carried out by the PMA are notused in this situation.

Generator Switch with Built-in Short-Circuit Release (Option)

If a generator switch is used which has its own short-circuit tripping,then an auxiliary contact of the generator switch is required in orderto form the short-circuit counting chain (contact open when there is ashort circuit). The short-circuit detection in the generator protectiondevice/measurement transducer should then sensibly be renderedinoperative.

Undelayed Short-Circuit Tripping (Option)

Some classes require undelayed tripping of the generator switch inresponse to particularly large short-circuit currents. An appropriatetripping device must be provided in the generator switch for thispurpose.

The tripping point is greater than the short-circuit current of a singlemachine set. Tripping can take place only when the short-circuit islocated between the generator and the generator switch or in thegenerator itself, and two or more generators which are operated inparallel with the faulty machine set can feed the short-circuit point.

In the PMA, one digital input is provided for connection of a signalingcontact for the undelayed short-circuit release (tripping=contactclosed). When tripping takes place, the following signals are emittedfrom the PMA:

Disconnection of generator switches

Machine set stop command

Block machine set

Switching to manual

Connection command to the next machine set

The following messages are displayed on the control panel:

“UNDELAYED SHORT-CIRCUIT TRIPPING” (SM) “BLOCKED” (BM) “SEMI” (BM)

Differential Protection (Option)

Beyond a certain generator power level, some classes requiredifferential protection. An external differential protection monitoringdevice must be provided for this purpose.

One digital input of the PMA is provided for connection of a signalingcontact of the external differential protection monitoring device(tripping=contact closed). When tripping takes place, the PMA emits thefollowing signals:

Disconnection of generator switches

Machine set stop command

Block machine set

Switching to local semiautomatic mode

Connection command to the next machine set

The following messages are displayed on the control panel:

“DIFFERENTIAL PROTECTION TRIPPED” (SM) “BLOCKED” (BM) “SEMI” (BM)

7.9 Table of the generator protection functions (Table 7.8) DISCON-DISCON- DISCON- DISCON- STANDBY NECTION NECTION NECTION NECTION BLOCKTIME MACHINE OF OF OF OF MA- SWITCHING LIMIT VALUE SET UNWANTED UNWANTEDUNWANTED GENERATOR CHINE MOTOR Auto → VALUE IN % s REQUEST LOAD 1 LOAD 2LOAD 3 SWITCHES SET STOP Semi GENERATOR CURRENT 1 95 30 X 2 100 5 X 3100 5 X(1) 4 100 10 X(1) 5 100 15 X(1) 6 120 1 X X(1) X(1) X(1) 7 110 30X(1) X X X GENERATOR POWER 1 95 30 X 2 100 5 X 3 100 5 X 4 100 10 X 5100 15 X 6 110 1 X X X X 7 −10 6 X(1) X X X BUSBAR FREQUENCY 1 97.5 60 X2 95 8 X(3)(4) 3 95 6 X 4 95 10 X 5 95 15 X 6 90 1 X(3) X X X 7 90 15 XX X X 8 105 2 GENERATOR VOLTAGE 1 90 5 X(3) (4) 2 60 1 X X X X 3 105 5X(3)(4) 4 110 5 X(2) (1)Function provided in the GENOP 71 (independentlyof the S7-300 PLC) (2)In addition, the generator is switched off(3)Switching takes place via blackout, once the newly started machineset is ready to be connected.

Power Management

The power management has the following tasks:

-   -   Starting a standby machine set in the event of overcurrent,        overload, underfrequency    -   Definition of the starting sequence of the standby machine set    -   Selection of a minimum number of generators (option)    -   Time-delayed disconnection of generators which are not required        (underload)    -   Definition of disconnection sequence for the unrequired        generators    -   Control of the busbar frequency (constant frequency or with        voltage droop)    -   Real load distribution between the generators (proportional to        the ratings or nonuniform load distribution)    -   Reactive load distribution (option)

Connection Chain

The connection chain is used to preselect which machine set will be thenext to be started in the event of a request from the PMA 71 (overload,overcurrent etc.). This function may be carried out from any controlpanel.

The “START/STOP SEQUENCE” submenu is displayed by pressing “ENTER” twiceand ↓ once on the control panel, as follows:

START/STOP SEQUENCE INPUT 1. GEN.: 1/3 : 1 ———— Transfer number with“ENTER” 2. GEN.: 2/4 : 2 3. GEN.: 4/2 : 4 4. GEN.: 3/1 : 3 . . . 13.GEN.: 0/0 : 0 Cnfrm: 1 ——————— Transfer new Start/Stop sequence using“ENTER”

The new start sequence is entered in the “INPUT” column. Each input mustbe confirmed using “ENTER”. The ↓↑ keys are used to jump from line toline.

The new sequence is accepted by entering a “1” in the “Cnfrm” line, andthen by pressing “ENTER”. The new start/stop sequence is now shown inthe “Start/Stop” column. Double inputs and incorrect inputs are rejectedby the error message:

“NOT POSSIBLE TO CHANGE THE START/STOP SEQUENCE”

Stop as a Result of Underloading

Preconditions:

Automatic mode

Function is enabled

Machine set is not running in the “UBL mode”

General

A machine set is stopped in the event of underloading. This is done bycomparing the generator real power with a limit value. There are threedifferent limit values for parallel operation of 2, 3 and 4 or moremachine sets. The limit values must be set such that the remaining loaddoes not lead to a repeated request for a standby machine set.

Disconnection Sequence

The disconnection sequence is the opposite of the connection sequence.The connection sequence is preselected on the control panel (seeconnection chain). If a machine set is not ready to be disconnected onthe basis of the disconnection sequence, for example because it is notready or is not in the automatic mode, then the next in the sequence isdisconnected.

If the start sequence is 1>2>3, then the stopping sequence is 3>2>1. Themachine set that is the next to be stopped in the event of underloadingis indicated as the “NEXT STOP” in the control panel.

Disconnection Process

In the event of underloading, the following message is output on thecontrol panel after an adjustable delay time (standard time 30 seconds).

UNDERLOADING

A “Stop with load reduction” is carried out after an adjustable delaytime of 10 minutes (standard) and the machine set is stopped. Thefollowing message appears on the control panel:

UNDERLOADING, MACHINE SET BEING STOPPED”

Once the stopping time has elapsed, the machine set is available onceagain.

Block Disconnection Chain

The stop as the result of underloading function can be blocked from thecontrol panel. The following text is displayed in the second submenu:

The “ENABLE STOP SEQUENCE” submenu is displayed as follows by pressing“ENTER” twice on the control panel:

ENABLE DISCONNECTION CHAIN DISCONNECTION CHAIN Active ACTIVE/DEACTIVE 1

The disconnection chain is enabled or inhibited by entering “1” or “0”as well as “ENTER”. If the disconnection chain is inhibited, then allthe machine sets which are connected to the power supply system remainconnected to it, even if underloading occurs in the on-board powersupply system.

Standby Start as a Result of Overcurrent

The actual value of the three generator currents I_(L1)/I_(L2)/I_(L3) ispassed from the generator protection device/measurement transducer tothe PLC where the currents are monitored to determine whether theyexceed three different limit values. If at least one of the currentsexceeds a limit value, a standby machine set is requested once a delaytime has elapsed. The limit values and times are staggered such that thelimit value being exceeded to a minor extent results in a slow reaction,while the limit value being exceeded to a major extent results in a fastreaction.

The following message is displayed on the control panel:

“STANDBY-START” (SM) or

The limit values and delay times can be changed via the control panel.The function is password-protected. The association between theindividual functions and the limit values as well as the standardsettings are shown in Table 7.8.

Standby Start as a Result of Overload

The actual value of the generator real power is passed from thegenerator protection device/measurement transducer to the PLC where thereal power is monitored to determine whether it exceeds three differentlimit values. If a limit value is exceeded, a standby machine set isrequested after a delay time has elapsed. The limit values and times arestaggered such that the limit value being exceeded to a minor extentresults in a slow reaction, while the limit value being exceeded to amajor extent results in a fast reaction.

The following message is displayed on the control panel:

“STANDBY-START” (SM) or

The limit values and delay times can be changed via the control panel.The function is password-protected. The association between theindividual functions and the limit values as well as the standardsettings are shown in Table 7.8.

Standby Start as a Result of Underfrequency

The actual value of the power supply system frequency is passed from thegenerator protection device/measurement transducer to the PLC where thepower supply system frequency is monitored to determine whether itexceeds three different limit values. If a limit value is exceeded, astandby machine set is requested after a delay time has elapsed. Thelimit values and times are staggered such that the limit value beingexceeded to a minor extent results in a slow reaction, while the limitvalue being exceeded to a major extent results in a fast reaction.

However, the standby machine set is synchronized only for the firstlimit value (very minor discrepancy). In the other two cases, a standbymachine set which has been run up is switched via “blackout”. (Thisfunction is explained in Section “Underfrequency/overfrequency”).

The following message is displayed on the control panel:

“STANDBY-START” (SM) or

The limit values and delay times can be changed via the control panel.The function is password-protected. The association between theindividual functions and the limit values as well as the standardsettings are shown in Table 7.8.

Real Load and Frequency Regulation

The signals from the frequency regulator and from the real powerregulator are both passed to assessment stages. The outputs of theassessment stages are passed to a stepping regulator, which produces“higher” or “lower” pulses for the machine set speed regulator.

The load regulator factor is higher than the frequency regulator factor,so that the influence of the real power regulator is greater than thatof the frequency regulator. Thus, load distribution is first of allcarried out between the machine sets, and the frequency is regulated atthe appropriate nominal value only after this has been done.

Real Load Regulation

Two different operating modes are possible:

Paritetic load distribution

Unbalanced load

Paretetic Load Distribution

In this operating mode, each generator produces power on the basis ofits rated values.

Power

UBL mode

In this operating mode, a generator accepts as much load as possible(UBL max.) but not more than a selected maximum value. The other machineset accepts as little load as possible, but not less than a selectedminimum value (UBL min.). The minimum value has a higher priority thanthe maximum value.

Frequency Regulation

Two different operating modes are possible:

Constant frequency regulation

Frequency regulation with frequency droop

Constant Frequency Regulation

In this operating mode, the power supply system frequency is regulatedsuch that it is constant at the rated frequency.

Frequency Regulation with Droop

In this operating mode, the power supply system frequency is regulatedin accordance with a curve. The curve is based on the generator power.The nominal values are in general selected such that the rated frequency(60 or 50 Hz) is achieved at 70 . . . 80% power. The no-load frequencyis about 2 Hz higher.

The profile of the power supply system frequency in response to loadchanges in the power supply system (frequency regulation with droop) isshown in FIG. 3.

Generator Switch Monitoring

Generator Switch “ON” Monitoring

The “On” acknowledgement from the generator switch is monitored. If theacknowledgement does not appear within a variable time after the “ON”command, then the SM

“GENERATOR SWITCH ON ACKNOWLEDGEMENT FAULTY”

is output.

Generator switch “OFF” monitoring

The “Off” acknowledgement from the generator switch is monitored. If theacknowledgement does not appear within a variable time after the “Off”command, then the SM

“GENERATOR SWITCH OFF ACKNOWLEDGEMENT FAULTY”

is output.

Generator Switch “ON/OFF” Monitoring

The “On” acknowledgements and the “Off” acknowledgements from thegenerator switch are monitored for plausibility. If neitheracknowledgement appears or both are present, then, after a variabletime, the SM

“GENERATOR SWITCH ON/OFF ACKNOWLEDGEMENT FAULTY”

is output.

Second Connection Command

In certain on-board power supply system conditions, it may be worthwhileconnecting two new machine sets in the event of a fault. This can beselected in the event of:

Blackout

Shutdown of one machine set

In this situation, the faulty machine set outputs two connectioncommands.

If one of the machine sets that is to be connected has a start fault, afurther connection command is output to a third machine set, if there isone.

Generator Protection and Synchronization Device GENOP 71

The generator protection and synchronization device GENOP 71 providesthe generator protection, with the following functions:

-   -   Short-circuit detection    -   Monitoring for overcurrent in each phase    -   Monitoring for reverse power    -   Disconnection of unimportant loads    -   Automatic synchronization of the generator to the busbar    -   Detection, processing and transfer of different measurement        values via the Profibus

FIG. 4 shows the GENOP 71 connections. Genop integrated in the PMA 71system. FIG. 5 shows the Genop 71 integrated in the PMA 71 system. TheGenop and the Simatic-S7 communicate via the Profibus DP. The parametersfor synchronization and generator protection can be changed via thecontrol panel OP7.

See Section 13 for more information about control.

Genop 71 as an Individual Device

The Genop 71 may also be used as an individual device, as is shown inFIG. 6. The parameters for synchronization and generator protection canbe changed via a serial interface (RS 232).

Test of the Device

The device should be tested once a year for correct operation. If thegenerator controller is designed in accordance with the standard circuitdiagrams, then there will be a test set for testing the generatorprotection.

The cable from the test set is plugged into the test plug. A lamp foreach phase now illuminates on the test set. There is a fuse behind eachof the lamps, providing protection for the test set.

A current of 1 A or 5 A can be preselected on the secondary side in eachphase, and can be set on the rotary knob. The instrument is alsoswitched in this process. The current can be read on the appropriatescale. The direction of the current is set on a second switch. In the“Normal” position, the current direction is simulated from the generatorto the power supply system, and in the “Reverse” position, the currentdirection is simulated from the power supply system to the generator.The ammeter in the switchgear assembly also operates in this case whenthe changeover switch ammeter is switched to the correct position.

The tripping point for shedding the unimportant loads and fordisconnection of the switch as a result of overcurrent can now beapproached for each phase by increasing the current in each phase. Whenchecking the power settings, care must be taken to ensure that thecurrents are increased uniformly in the individual phases, in order toavoid spurious tripping as a result of one current possibly having beenset too high.

Configuration Via a PC

If the Genop is in the form of a single device, then the settings can bemade by way of a PC. The connecting cable to the PC is plugged to theserial interface. The configuration program is started by clicking themouse on the “Genop 71” icon. The standard menu is displayed.

Load

The stored setup of a Genop can be loaded in the configuration program.The loading process does not automatically result in the parametersbeing transferred to the Genop 71.

Save

Stores the currently edited data from the configuration program. If thedata has not yet previously been stored, then a file name is asked forfirst of all. The extension is always “Gen”.

Save as

This allows a path and file name to be entered before storing aparameter record.

Transmit Data

Transmits all the parameter values set in the configuration program tothe Genop 71.

Receive Data

Loads all the parameters that are currently in the Genop 71 into theconfiguration program.

Print

All the values contained in the configuration program are printed.

Exit

Ends after checking the configuration program.

Edit

Limit values + Delay times Parameter Meaning Current 1 Generator currentlimit value: if the limit value is exceeded, the unimportant loads aredisconnected with a time delay in stages, stages 1–3 Current 2 Generatorcurrent limit value: (Not used) Current 3 Generator current limit value:if the limit value is exceeded, the unimportant loads are disconnectedwith a short time delay (1 s), stages 1–3 Current 4 Generator currentlimit value: if the limit value is exceeded, the generator switch isdisconnected with a time delay (15 seconds, as standard) Reverse PowerReverse power limit value: if the limit value is exceeded, the generatorswitch is disconnected with a time delay (6 seconds as standard) Shortcircuit Short circuit: if exceeded, the generator switch is disconnectedwith a short time delay (0.2–0.6 seconds) Delay Time 1 The delay timestarts after the limit (Current 1) value “Current 1” has been exceeded,and disconnects the unimportant loads, stage 1, when the time haselapsed Delay Time 2 The delay time starts after the limit (Current 1)value “Current 1” has been exceeded, and disconnects the unimportantloads, stage 2, when the time has elapsed Delay Time 3 The delay timestarts after the limit (Current 1) value “Current 1” has been exceeded,and disconnects the unimportant loads, stage 3, when the time haselapsed Delay Time 3.1 The delay time starts after the limit (Current 3)value “Current 3” has been exceeded, and disconnects the unimportantloads, stages 1–3, when the time has elapsed Delay Time 4 The delay timestarts after the limit (Current 4) value “Delay Time 4” has beenexceeded, and switches off the generator switch after the time haselapsed Delay Time 5 The delay time starts after the limit (ReversePower) value “Delay Time 5” has been exceeded, and switches off thegenerator switch after the time has elapsed Delay Time 6 The delay timestarts after the limit (Short Circuit) value “Delay Time 6” has beenexceeded, and switches off the generator switch after the time haselapsed

Internal Parameters Parameter Limits Meaning Sync.Short-Pulse Shortpulse length synchronization Length Short-Pulse Pulse Factor for settingthe ratio Ratio between the pulse-pause time of the short pulses forsynchronization. If the setting is 100%, the pulse/pause time is equal.If the setting is 50%, the pause time is 50% of the pulse timeSync.Long-Pulse Long pulse length synchronization Length Long-PulsePulse Factor for setting the ratio Ratio between the pulse/pause time ofthe short pulses for synchronization. If the setting is 100%, thepulse/pause time is equal. If the setting is 50%, the pause time is 50%of the pulse time Frequ. Limit Limit value switching from Switching fromcontinuous to long pulse Permanent to Long Pulse Length Frequ. LimitLimit value switching from long Switching from Long pulse to short pulseto Short Pulse Length

Sync.Enable Limits Parameter Limits Meaning Sync.Diff.FrequencyDifference between generator and Limit power supply system frequency. Ifthe limit value is exceeded, then the adjusting pulses are inhibited.Sync.Diff.Voltage Voltage difference between Limit generator voltage andpower supply system voltage. If the limit value is exceeded, then theconnection of the generator switch and the output of adjusted pulses areinhibited. Sync.Connecting Difference between generator and Limit powersupply system frequency where synchronization is in fact still possible.If the limit value is exceeded, then switching on the generator switchis inhibited. However, adjusting pulses are still output for frequencyadjustment Pre-Switching Time Calculated time between outputting thegenerator switching-on command and the zero crossing of the beat voltageSwitch ON Pulse Length of the generator switching- Length on pulse

U + I Transformation Parameter Meaning Primary Voltage Rated voltage ofthe power Transformer supply system Primary Current Rated voltage of theTransformer generator

Extras

Trigger Controlling

A Genop 71 must be connected for activation of this function. This menuallows the limit-value tripping operations for Current 1–4, reversepower and short circuit to be suppressed.

Generator Frequency

The generator frequency can be adjusted here by clicking the mouse.

Precondition:

-   -   The voltage difference (power supply system/generator) is less        than the value set in the “Sync.Diff.Voltage Limit”    -   The frequency difference (power supply system/generator) is less        than the value set in the “Sync.Diff.Frequency Limit”.

PC Interface

The number of the serial interface (COM Ports 1–3) can be selected.

About GENOP 71

This menu item shows the version data of the parameter program and thefirmware for the Genop 71 that is connected. The menus “Show Data”,“Control-Signals” and “Adjustments” are provided only for work at themanufacturer's premises.

Generator Protection

Overcurrent Time Protection

The three generator currents IL1, IL2, IL3 are detected by measurementtransducers. The extreme values of the three currents are monitored forlimit values.

The following table shows the generator protection function:

Generator current Relay Limit Delay generator value I in time RelayRelay Relay switch (GW) % sec. GW1 GW2 GW3 off GW1 100 5 s x 10 s x 15 sx GW3 120 1 s x x x GW4 110 30 s x Reverse power Relay Delay generatorLimit P in time Relay Relay Relay switch value % sec. GW1 GW2 GW3 offGW5 0–100 6 s x Short circuit Relay Delay generator Limit time RelayRelay Relay switch value I in % sec. GW1 GW2 GW3 off GW6 >300   0.1–1.5s x

FIG. 7 shows the functional relationship for generator protection.

FIG. 8 shows the functional relationship for disturbance evaluation.

The disturbance message signals which occur for generator protection aremaintained until they are acknowledged by the high-level control system,or are canceled by a RESET. The failure of the 24V battery voltage or adefect in the computer results in unavoidable signaling by tripping ofthe “System Defect” relay.

Synchronization

Frequency Adjustment

Once the machine set has been started, the power supply system frequencyis approached first of all with continuous adjustment commands, followedby long and short pulses. The comparison as to whether the power supplysystem frequency is greater than or less than the generator frequency iscarried out in the GENOP 71 generator protection and synchronizationdevice.

If f generator is <f power supply system, the signal “1” appears at the“HIGHER” output. If f generator is >f power supply system, the signal“1” appears at the “LOWER” output. The length of the HIGHER/LOWERadjusting pulses can be changed on the control panel.

Beat Voltage Detection and Evaluation

The beat voltage which is obtained from the synchronization device isevaluated for synchronization of the generator switch. The beat voltageis produced by comparing the power supply system voltage and thegenerator voltage. The gradient of the beat voltage changes in acorresponding manner to the difference between the generator frequencyand the power supply system frequency. The gradient of the beat voltagecurve as obtained from the measured values is evaluated, and theswitch-on command is produced with the appropriate lead.

Lead

The lead time (time between the switch-on command and the closing of thegenerator switch) can be set on the control panel, on the basis of thegenerator switch data.

The following table shows the permissible lead times in the ratio of thegenerator frequency to the busbar frequency.

Generator/busbar Lead time max. n difference frequency [HZ] [ms] 0.2 4560.3 276 0.4 192 0.5 204 0.6 146 0.7 128 0.8 88 0.9 60 1.0 58

Difference Frequency

The difference frequency between the power supply system frequency andthe generator frequency is likewise derived from the beat voltage. Ifthe difference frequency is >0.5 Hz, synchronization is inhibited. Ifthe difference frequency is >10 Hz, the HIGHER/LOWER adjusting pulsesare inhibited entirely, since this indicates that a machine set faultmust be present.

Frequency Tuning

If the generator frequency is made very close to the power supply systemfrequency by way of a tuning command, so that continuous beating occurs(power supply system frequency and generator frequency are the same),then this results in an adjusting pulse and a greater Delta-f isproduced in order to allow rapid synchronization. This is done byevaluating the beat frequency zero crossings. If no zero crossing occursin the beat frequency within a specific time, another adjusting pulse isproduced.

Automatic synchronization/synchronization in the local semiautomaticmode and synchronization in the manual mode are described in Section 4.

Adjustable Values for Synchronization

Some values for synchronization can be adjusted via the OP7. If thegenerator protection device/measurement transducer GENOP 71 is used onits own, these values can be set via a PC program.

The following values can be set.

-   -   Limit value for the difference frequency for enabling the        adjusting pulses (for example 10 Hz)    -   Limit value for the difference frequency for switching from        continuous pulse to long pulse (for example 1.5 Hz)    -   Limit value for the difference frequency for switching from long        pulse to short pulse (for example 0.6 Hz)    -   Limit value for the difference frequency for switching the        generator switch at a zero crossing (for example 0.5 Hz)    -   Pulse length of the short pulses    -   Pulse length of the long pulses    -   Lead time to reach the zero crossing of the beat voltage        (switch-on time for the generator switch)    -   Pulse length of the switch-on command for the generator switch    -   Trip delay time for initiating frequency tuning    -   Pulse length of the “Higher/Lower” pulses for frequency tuning    -   Limit value for the difference between the generator voltage and        the power supply system voltage for inhibiting the adjustment        process and connection of the generator switch

Voltage Difference Monitoring

The connection of the generator switch is blocked if the voltagedifference is too great. If the voltage difference is greater than thelimit value which can be selected, then the connection of the generatorswitch and the outputting of the adjusting pulses are inhibited. Thefact that the limit value has been exceeded is signaled by an LED on thefront face of the device.

Optionally, a voltage regulator can be provided in the Simatic-S7, whichoutputs higher/lower adjusting pulses to the voltage regulator for thegenerator.

FIG. 9 shows the functional procedures for synchronization

Meaning of the parameters: BR_ON Switch ON signal SYN_EN Enablesynchronization AUT_EN Automatic mode F_HIGHER Frequency adjustingpulse, higher F_LOWER Frequency adjusting pulse, lower

FIG. 10 shows the principle of synchronization.

24V DC/24V DC Isolating Transformer

Object

The 24V DC/24V DC isolating transformer has the following functions:

-   1.) The connected components can be operated over a wider frequency    range than is possible on the basis of the technical data for the    individual components.-   2.) The connected components are DC-decoupled from the marine vessel    battery. The 24V DC supply voltage can be grounded downstream from    the isolating transformer, and this has major advantages for    disturbance protection.

The following components are fed from the power supply:

-   -   The SIMATIC S7 associated with the machine set    -   All the signal sensors which are associated with the machine set        and the control system    -   The digital outputs from the SIMATIC S7 (operation of lamps or        coupling relays)    -   The generator protection device/measurement transducer    -   The OP7 control panel

The power supply for the generator protection device/measurementtransducer is designed in a redundant manner, that is to say in additionto the feed from the isolating transformer (and thus from thehigher-level battery power supply), this device has a feed from a powersupply unit, which is fed from the respective generator.

The voltage supply for the undervoltage coil for the generator switch aswell as the delay time is not included in the PMA 71 but must beinstalled in the switch panel.

Mechanical design:

The 24V DC/24V DC isolating transformer is mounted on the mounting plateby way of a number of screws. It may be mounted horizontally orvertically. Input and output voltage are connected via Faston pins.

FIG. 11 shows the standard OP7 control panel (BT).

The invention being thus described, it will be obvious that the same maybe varied in many ways. Such variations are not to be regarded as adeparture from the spirit and scope of the invention, and all suchmodifications as would be obvious to one skilled in the art are intendedto be included within the scope of the following claims.

1. A marine electrical system for a marine vessel, comprising: systemcomponents; and standard modules, wherein the system components areadapted to be controlled and regulated by the standard modules, whereinthe standard modules operate digitally in all operating states, andwherein each of the standard modules are provided only for controllingand regulating one of the system components.
 2. The marine electricalsystem as claimed in claim 1, wherein the respective standard moduleswhich operate digitally and are provided only for controlling andregulating one of the system components are connected via a bus system.3. The marine electrical system as claimed in claim 2, wherein the bussystem is a Profibus (Process Field Bus) system.
 4. The marineelectrical system as claimed in claim 2, wherein components of themarine electrical system include at least one of standard switch panelsand standard switchgear cabinets.
 5. The marine electrical system asclaimed in claim 1, further comprising programmable logic controllers.6. The marine electrical system as claimed in claim 5, wherein themarine electrical system is adapted to be programmed at any time.
 7. Themarine electrical system as claimed in claim 5, wherein the programmablelogic controllers include Siemens SIMATIC S7 programmable logiccontrollers.
 8. The marine electrical system as claimed in claim 5,wherein components of the marine electrical system include at least oneof standard switch panels and standard switchgear cabinets.
 9. Themarine electrical system as claimed in claim 1, further comprisingcontrol and monitoring appliances, adapted to be run using Windows. 10.The marine electrical system as claimed in claim 1, wherein componentsof the marine electrical system include at least one of standard switchpanels and standard switchgear cabinets.
 11. The marine electricalsystem as claimed in claim 1, further comprising a power generatorautomatic system, a control automatic system, a regulation automaticsystem and a switching automatic system.
 12. The marine electricalsystem as claimed in claim 11, wherein the power generator automaticsystem is designed to optimize the power generation on a financialbasis.
 13. The marine electrical system as claimed in claim 1, furthercomprising generator protection functions.
 14. The marine electricalsystem as claimed in claim 1, further comprising generatorsynchronization appliances.
 15. The marine electrical system as claimedin claim 1, further comprising control panels for control andobservation, measurement converters and isolating transformers.
 16. Themarine electrical system as claimed in claim 1, wherein the marineelectrical system is designed such that a choice of operating modes isprovided for at least one of individual operation and group operation ofthe generators.
 17. The marine electrical system as claimed in claim 1,wherein the system components are adapted to be controlled and regulatedby the standard modules in the form of generators, electrical loads andan on-board power supply system with switchgear assemblies, and whereinthe marine electrical system ensures that adequate electrical power isprovided in all operating states of the ship.
 18. The marine electricalsystem as claimed in claim 17, further comprising programmable logiccontrollers.
 19. The marine electrical system as claimed in claim 18,wherein the programmable logic controllers include Siemens SIMATIC S7programmable logic controllers.
 20. The marine electrical system asclaimed in claim 18, wherein the marine electrical system is adapted tobe programmed at any time.
 21. The marine electrical system as claimedin claim 19, wherein the marine electrical system is adapted to beprogrammed at any time using a programming language Step
 7. 22. Themarine electrical system as claimed in claim 17, wherein components ofthe marine electrical system include at least one of standard switchpanels and standard switchgear cabinets.
 23. The marine electricalsystem as claimed in claim 17, further comprising a power generatorautomatic system, a control automatic system, a regulation automaticsystem and a switching automatic system.
 24. The marine electricalsystem as claimed in claim 23, wherein the power generator automaticsystem is designed to optimize the power generation on a financialbasis.
 25. The marine electrical system as claimed in claim 17, furthercomprising generator protection functions.
 26. The marine electricalsystem as claimed in claim 17, further comprising generatorsynchronization appliances.
 27. The marine electrical system as claimedin claim 17, further comprising control panels for control andobservation, measurement converters and isolating transformers.
 28. Themarine electrical system as claimed in claim 17, wherein the marineelectrical system is designed such that a choice of operating modes isprovided for at least one of individual operation and group operation ofthe generators.